It was a tragic, ironic twist to an otherwise heartwarming story: A hitchhiking author working on a book about the kindness of strangers was shot by one of those strangers.

Ray Dolin told police that he was shot in the arm by a stranger in a car, apparently at random, who then sped off before he could get a good look at his assailant. Police soon arrested a suspect for the crime but released him after GPS evidence proved he was nowhere near Dolin at the time of the attack. A few days ago Dolin admitted to shooting himself in the arm and making up the story; according to Valley County Sheriff Glen Meier, Dolin "made a full confession."

Why would a person go to all the trouble (not to mention pain, in the case of self-inflicted wounds) to hoax a report?

Dolin did not explain why he committed the hoax, but it's widely believed that the motive was publicity for his book. The infamous "Balloon Boy" hoax in 2009 is another example, in which the parents of a boy who supposedly flew away on a homemade balloon were allegedly hoping the attention would help them land a reality TV show deal.

Some seek attention and sympathy as victims, while others simply commit hoaxes for fun and the enjoyment of watching their handiwork make local or national news.

Sometimes people commit faked attacks to promote social or political agendas. For example, in April 2008 Melanie Bowers, an eighth grader at Athens Middle School in Texas, made a poster for a school project that said, "If you love our nation, stop illegal immigration." She claimed that a mob of angry students outraged at her poster ripped it up, beat her, slammed her head against a brick wall, and tried to drag her into a bathroom where several boys threatened to rape and kill her. Bowers accused nearly two-dozen students in the attack, and three Hispanic students were suspended. The race-tinged accusations made national news, and fueled anti-immigration sentiment. However the school's surveillance cameras proved that she lied; she was seen scratching her own face and arms to make it look like she'd been attacked. [The 10 Most Destructive Human Behaviors]

People often fake assaults and robberies to cover up money losses due to gambling, drug use, strip clubs, and even illicit affairs. For many people it's easier to say that a stranger stole several hundred dollars than to admit to a spouse or friends what it was really spent on.

Sometimes people who falsely report crimes really are victims — not of the crimes they claim but of crimes they can't legally report (for example getting ripped off on a drug deal), or even crimes they are embarrassed to admit to being victims of. That's what happened in 2004 when Academy Award winning actor Kevin Spacey reported that he'd been the victim of a mugging and robbery while walking his dog in a park in London, England. Spacey, bleeding from a head wound, told police that a stranger assaulted him and stole his cell phone. Spacey later admitted that he had in fact been conned; a kid asked to borrow his cellphone to make a call, and ran away with it. Spacey tripped over his dog running after the thief, injuring his head in the process.

Many accidental self-inflicted gunshot wounds — including by police — are blamed on unknown assailants because the "victims" don't want to admit they were careless with their weapons. In April 2012 veteran Philadelphia police sergeant Robert Ralston claimed that during a traffic stop of two black men one of them shot him in the shoulder and ran away. A massive search was launched for the criminals but no one was found; Ralston finally admitted to investigators that he'd accidentally shot himself. No criminal charges were filed in exchange for his confession.

Self-inflicted wounds provide the hoaxer with tangible evidence of the attack and strong credibility. As Dolin discovered, however, faked gun crimes are taken very seriously. If a gun was used in an attack or the commission of a crime, that automatically increases the severity of the crime and triggers a more robust police response. If Dolin had merely reported that he’d been threatened, or even beaten up, by an unknown assailant (and there were no eyewitnesses or videotapes to dispute his story), he likely would have gotten away with it.

Benjamin Radford is deputy editor of Skeptical Inquirer science magazine and author of Scientific Paranormal Investigation: How to Solve Unexplained Mysteries. His website is www.BenjaminRadford.com.